Peroxymonosulfate activation for preferential generation of hydroxyl radical with atomic Mn anchored TiO2 in photoelectrochemical process

Abstract

The threaten of ubiquitous antibiotics to human and ecosystem makes it urgent to seek efficient treatment technologies. Peroxymonosulfate (PMS)-based advanced oxidation processes have revealed wide prospects for wastewater treatment via controllable PMS activation for desired ROS generation. Herein, a novel TiO₂ photoelectrode decorated with atomically distributed Mn (SA-MnTiO₂) was designed via a modified molten salt method (MSM) for photo-electro-catalytic (PEC) activation of PMS. The electron transfer in reduction-/oxidation-state Mn(II)/Mn(III)/Mn(IV) cycles facilitated the cleavage of intramolecular O–O bonds in PMS to preferentially generate hydroxyl radical (HO•). Almost complete degradation of norfloxacin (NOR) was occurred with optimal SA-Mn_0.6TiO₂ within 15 ​min, exhibiting high turnover frequency (0.066 min⁻¹). Around 74.8% of total organic carbon was eliminated with a low specific energy consumption of 0.94 ​kW ​h/g. The key operational parameters during actual wastewater treatment were inspected for SA-Mn_0.6TiO₂/PMS system, suggesting the satisfactory stability for practical applications.